Tire pressure gauge



P 1932- J. c. FAIR TIRE' PRESSURE GAUGE Filed July 7, 19:50

@Z/eJZZ OZ. K/ $329k 6' air.

Patented Sept. 6, 1932 fem-ran; STATES aosnrrr c. we, or roam WAYNE, INDIANA TIRE PRESSURE GAUGE Application filed July 7, 1930. Serial N0. 4 65,865.

The purpose of this invention is to provide a relatively simple portable gauge device adapted for determining the degree of infiation of a pneumatic tire or the like, and i fvidedwith a centrally located curved socket, 5 inwhich isseated the rounded nose, 6 f

5 particularly arranged for making such determination without access to the interior of the tire. t consists of certain features and elements of construction in combination, as herein shown and described and as indicated In by the claim.

In the drawing:

Figure 1 is a partial side elevation of a vehicle tire and of the gauge device embodying this invention, showing the method of using the latter.

Figure 2 is a side elevation of the gauge on a larger scale and showing it inverted as compared with the position of use illustrated in Figure 1.

Figure 3 is a transverse vertical section on an enlarged scale.

Figure 4: is a section taken as indicated at line 4-4 on Figure 3, drawn substantially tothe same scale as Figure 2.

Figure 5 is an end view of the device.

Figure 6 is an enlarged fragmentary view showing the equalizer for the springs.

As shown, the device embodying this invention includes a body or housing having a handle portion, 1, and preferably integral therewith a frame portion, 2, which supports a dial plate, 8, and terminates in a stop shoulder, 1. Slidably mounted in the frame and handle is a plunger, 5, normally protruding past the plane of the stop shoulder, 4:, and yieldingly held in that position by compression springs, 6, 6, pocketed in the handle, 1. In addition to the dial plate, 3, the frame, 2, supports a back plate, 7, said plates being in formed to be lodged in suitable recesses of the frame in spaced relation to each other with the plunger, 5, extending between them.

A spacer sleeve, 8, extending between the plates, 3 and 7, accommodates a bolt, 9, wh1ch n") serves as a pivot for an indicating needle or hand, 10, mounted adjacent the dial plate, 3, at the outer side thereof for swinging about such pivot to traverse the graduations marked on the face of the dial plate, 3. The dial plate so has an arcuate slot, 11, through which a bent lug, 12, of the needlemember, 10, projects for engagement by a lug, 13, formed on the plunger, 5. V

The lower end of the plunger, 5, is proan equalizer block, 6", disposed below said plunger, as seen in Figure 6. 'Said block is provided with a pair of spaced bosses, 6, adapted to engage in the ends of the springs, to 66, for maintaining them in a definite position. Thus the block is free to rock about its 'ball-and-socket mounting to accommodate the differences in pressure of said springs. I

For determining the pressureto which a tire such as that indicated at A 'in Figure 1,

has been inflated, the gauge device is applied 'as shown with the end of the plunger, 5, in

contact with the surface of the tire, and with the whole device pressed toward the tire 71 until the stop shoulder, 4, also engages its surface. It will be seen that if the tire were absolutely rigid the plunger, 5, would thus be depressed inwardly to bring its outer end flush with the shoulder, 4:, but the yield- 75 ing nature of the tire permits the plunger, 5, to protrude past the plane of the shoulder, 4, to an extent depending upon the pressure of the air in the tire. In other words, the air pressure in the tire is balanced against the compression springs, 6, -6,'which oppose it through the plunger, 5. Inward movement of the plunger, 5, fromthe normal position shown in Figure 2 causes this lug, 13, to engage the lug, 12, of the needle, 10, and swing the needle about its pivot through an angle corresponding to the depression of the plunger, 5. The graduations on the dial plate, 3, may be marked in terms of pounds pressure per-square inch corresponding to the various angular positions which the needle, 10, may assume, and thus the device will indicate the pressure of the air in the tire. i

Preferably the arcuate travel of the lug, 12, is so arranged that the radial'armvof the 5 lug, 12, with respect to its pivot is nearly perpendicular to the direction of, movement of the plunger, 5, through most of the range so that the angular movement offthe needle, 10, will be very nearly directly proportional 1.0

to the straight-line movement-of the plunger, 5. Inwso far as this is notstrictly true, the dial may be graduated accordingly, but in general the units of graduation will be about equal throughout the scale.

For calibrating the device or readjusting for any change in tension of the springs,

6, 6, there is provided an adjusting screw,

14, in the outer end of the handle, 1, which may impinge against a pressure plate, 15, serving as a seat for the outer endsof the springs, 6, 6.

It will be seen that whereas othergauges plunger.

V V JOSEPH C.v FAIR.

heretofore have been designed to imeasure directly the pressure of the air within the tire and were therefore required 'to be ,connected to the interior of the tire by removal of the usual filler cap and application to/the valved stem of the tire, 'the present device is muchv simpler tonuse sinceit provides for instantaneous indication of the. condition of the air pressure merely upon being; pressed against the body of the-tire. It will thus result in a great saving of time to the user,

and because of the extreme simplicity .of its use will encourage an ins ection of tire pressures to be made more 'requently and the air pressure to be-kept nearer a proper 7 value for securing the best riding qualities and longest life from the tire'su v Preferably, the needle, 12,;wl1ile rotatably mounted upon the enlarged portion, 16, of the bolt, 9, is provided with frictional resistance, against such rotation in, the form of a spring washer, 17, placed under the head, 18, of the bolt,'and in Contact with the hub portion of ,the needle, 10. As a, result, the

needle will remain at themaXimumindica-ting position to which it is moved by the inward depression of the plunger,'5, when the device is applied to the tire, while theplunger itself will return to normal position'as soon as the gau'gei's removed from the tire. This 7 makes the gauge a recordingjinstrument which may be read at leisure] after its removal from the tire instead of requiring the user ,to attempt-to read thescale with the device in position shown in Figure 1.

In the formlof the device illustrated the stop shoulder, 4, constitutes one surface of a flange, 19, and this fiange'projects laterally at 20 from two sides of the frame portion, 2,

forcing it agalnst the surface of the-tire, as illustrated in-Figure 1. This method of hold- :ing and applying the vgauge is not essential but will usually'be foundthe most convenlent.

I claimf I A gauge comprising a body having an ex- Vso, as toprovide surfacesagainst which the l fingers may apply pressure to the device in ternal stop shoulder, a plunger movably carried' in the body 'and' projecting normally past said slioulder with spring means pocketl i V edinthe'bodyyie1dmg1y ho ng said plung- 

